Inking devices of photogravure printing apparatus known at the present time generally comprise a sprayer for causing ink to flow over the peripheral surface of the engraved cylinder of the apparatus, which has cavities hollowed out therein, arranged in accordance with the pattern to be printed. These cavities are located over the greater part of the length of the cylinder, the two end parts or "stubs" of the cylinder being, on the contrary, left smooth. The sprayer is constituted by an inclined plane connected to a source of ink and it allows a quantity of ink to flow, under the sole action of gravity, quantity sufficient to obtain complete filling of all the cavities of the engraved cylinder when these cavities pass beneath the sprayer. Due to the provision of this sprayer, it is necessary to place, below the engraved cylinder, a receiver tank collecting the excess ink flowing from the sprayer and in which the lower part of the engraved cylinder is immersed.
Such a known inking device presents a certain number of drawbacks. Firstly, it is necessary, whenever the format is changed, to effect two adjustments, namely a vertical adjustment of the lower ink-receiving tank and a horizontal adjustment of the sprayer to take into account the variation in the diameter of the engraved cylinder. Furthermore, as indicated hereinabove, the lower part of the engraved cylinder is immersed in the ink contained in the receiver tank and, consequently, its two end parts or "stubs", not engraved, are coated with ink which is projected due to the rotation of the engraved cylinder. This results in that the speed of rotation of this engraved cylinder, and consequently the operational speed of the apparatus, are limited in order to avoid excessive projections of ink. Finally, the lower receiver tank must be cleaned often, this constituting a fairly long and difficult operation.
U.S. Pat. No. 3 815 499 already discloses an inking device comprising a hollow ink applicator means, parallel to the engraved cylinder and adjacent thereto over the whole length of its engraved part, in the descending movement of its generatrices, the inner volume of this applicator means being connected to a source of ink and communicating with an inking chamber defined, in the horizontal direction, by the ink applicator means, and means for adjusting the thickness of the film of ink formed from the inking chamber, on the peripheral surface of the engraved cylinder.
It is an object of the present invention to provide an inking device of particularly simple design, facilitating cleaning of the ink fountain, making it possible to obtain complete filling of the cavities in the engraved cylinder and always to maintain the non-engraved end parts of the cylinder clean, and avoiding the use, below the engraved cylinder, of a receiver tank and consequently the drawbacks involved thereby.